Anderson,
So long as you train for a JAA fATPL in America, you will save money. If you try to do an FAA ME/CPL/IR, then convert to JAA, it will take you an extra 9 months or so and probably cost £15-20K for the conversion.
JAA requires the IR be done in European airspace, so do the PPL, Night Qual and Hour building in the States. Next do JAA ATPL theory in Europe. Then do a JAA ME and CPL in the States. Then do the JAA IR and MCC in Europe.
Finally, I would recommend no more than two schools for the flying after ATPL theory. I spoke to a FlyBe recruiter recently who said they allow one school for ATPL theory and no more than two others for CPL/ME/IR/MCC. When I asked why, he said words to the effect that the FTOs can't really judge the character of students who spend less than a month with them. In other words, if you jump around a lot, they don't know whether it is because you are shopping for cheapest price or because you are a prat who doesn't get on anywhere. He indicated that the reason they allow two schools for the flying bit is because some very good modular schools do not offer MCC.